This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The current study will utilize diffusion tensor imaging and functional magnetic resonance imaging to investigate the anterior cingulate in 40 pediatric patients with obsessive compulsive disorder (OCD) and 40 healthy volunteers. Subjects will also provide DNA to investigate the genetic basis of brain abnormalites in OCD. We hope to improve our understanding of the role that the anterior cingulate plays in the neurobiology of OCD and whether abnormalities in this region can serve as endophenotypes in genetic studies of the disorder.